JP2017087451A - Printing device and printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing device and printing method which can sufficiently suppress occurrence of color unevenness and density unevenness and print a high quality image.SOLUTION: A printer includes a printing part which performs printing on a recording medium. When the movement direction of the printing part is defined as an x direction and the conveyance direction of the recording medium is defined as a y direction, the printing part includes a first head array in which a plurality of first heads are arranged in the y direction and a second head array in which a plurality of second heads are arranged in the y direction. The first head array and the second head array are adjacent to each other in the x direction. At least a pair of the first head arrays and at least a pair of the second head arrays are symmetrically arranged with the y direction as a symmetric axis. On each of the left side and the right side of the symmetric axis, the boundary of the first heads and the boundary of the second heads are shifted in the y direction.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a printing apparatus and a printing method.

  2. Description of the Related Art Printing apparatuses that perform printing on a sheet-like recording medium by an inkjet method are known. This printing apparatus includes a plurality of heads having a large number of nozzles, conveys the recording medium, and ejects ink while moving the head in a direction (main scanning direction) perpendicular to the recording medium conveyance direction (sub-scanning direction). It is configured to The printing apparatus has a configuration in which a head row in which heads are arranged in the sub-scanning direction is arranged in the main scanning direction for each ink color. Further, the ink ejected from each nozzle will land on the recording medium. Each landing area where the ink has landed constitutes a part of the image on the recording medium, and as a result, a collection of these landing areas is recognized as an image.

  The conventional printing apparatus has a configuration in which the head seams between adjacent head rows overlap. For this reason, the image portions printed at the joints of the respective head rows are overlapped with each other, resulting in a problem of color unevenness and density unevenness.

In order to solve such a problem, an attempt has been made to eliminate the density unevenness by shifting the joint between the heads of different color heads in the sub-scanning direction (see, for example, Patent Document 1 and Patent Document 2). .
However, with the conventional configuration, it has been difficult to form an image with sufficient image quality.

JP 2012-200920 A JP 2013-215993 A

  An object of the present invention is to provide a printing apparatus and a printing method capable of sufficiently suppressing occurrence of color unevenness and density unevenness and printing a high-quality image.

Such an object is achieved by the present invention described below.
The printing apparatus of the present invention includes a transport unit that transports a recording medium,
A printing unit that performs printing on the recording medium conveyed by the conveyance unit;
A moving unit that moves the printing unit in a direction that intersects the conveyance direction of the recording medium during the printing,
When the moving direction of the printing unit is the x direction and the conveyance direction of the recording medium is the y direction,
The printing unit discharges a first color ink, discharges a first head having a plurality of first nozzles arranged in the y direction, and discharges a second color ink in the y direction. A second head having a plurality of second nozzles disposed,
The first head constitutes a plurality of first head rows arranged in the y direction,
The second head constitutes a plurality of second head rows arranged in the y direction,
The first head row and the second head row are adjacent to each other in the x direction,
At least a pair of the first head rows and at least a pair of the second head rows are arranged symmetrically about the y direction as a symmetry axis,
A boundary portion between the first heads and a boundary portion between the second heads are shifted in the y direction on each of the left side and the right side of the symmetry axis.

  Thereby, occurrence of color unevenness and density unevenness can be sufficiently suppressed, and a high-quality image can be printed.

In the printing apparatus according to the aspect of the invention, the plurality of first heads of the first head row are alternately arranged in the y direction, and the central axis of the first head in the x direction is the x axis. A certain distance in the direction,
The plurality of second heads of the second head row are alternately arranged in the y direction, and the center axis in the x direction of the second head is shifted by a predetermined distance in the x direction. Is preferred.

  Thereby, the density unevenness of the image printed at the head boundary (seam) of each head row can be effectively suppressed.

  In the printing apparatus according to the aspect of the invention, the boundary between the first heads and the boundary between the second heads are shifted to the downstream side in the transport direction of the recording medium as they are separated from the symmetry axis. Is preferred.

  Thereby, generation | occurrence | production of a color nonuniformity and density nonuniformity can fully be suppressed, and a high quality image can be printed more effectively.

  In the printing apparatus according to the aspect of the invention, it is preferable that the transport unit includes a belt having adhesiveness with respect to the recording medium.

  Thus, the recording medium can be adhesively fixed when printing on the recording medium, and thus the printing can be performed stably.

In the printing apparatus according to the aspect of the invention, it is preferable that the moving unit is configured to move the printing unit so that the x direction is orthogonal to the y direction.
This facilitates control of the ink ejection timing for the recording medium.

  The printing method of the present invention is characterized in that printing is performed on a recording medium using the printing apparatus of the present invention.

  Thereby, occurrence of color unevenness and density unevenness can be sufficiently suppressed, and a high-quality image can be printed.

It is a side view which shows suitable embodiment of the printing apparatus of this invention. It is a block diagram of the principal part of the printing apparatus shown in FIG. FIG. 2 is a plan view illustrating an example of an arrangement of head rows in a printing unit included in the printing apparatus illustrated in FIG. 1. It is a top view which shows the boundary part of the heads in the printing part with which the printing apparatus shown in FIG. 1 is provided.

  Hereinafter, a printing apparatus and a printing method according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

  FIG. 1 is a side view showing a preferred embodiment of the printing apparatus of the present invention. FIG. 2 is a block diagram of a main part of the printing apparatus shown in FIG. FIG. 3 is a plan view illustrating an example of the arrangement of head rows in a printing unit included in the printing apparatus illustrated in FIG. 1. FIG. 4 is a plan view illustrating a boundary portion between heads in a printing unit included in the printing apparatus illustrated in FIG. 1. In the following, for convenience of explanation, the depth direction in FIG. 1 is referred to as “x direction”, the left and right direction as “y direction”, and the up and down direction as “z direction”. Also, the coordinate axes in FIGS. 3 and 4 respectively correspond to the coordinate axes in FIG.

  The printing apparatus 1 of the present invention is an apparatus that performs printing on the work W while conveying the work W as a recording medium, and can execute the printing method of the present invention.

  As shown in FIGS. 1 and 2, the printing apparatus 1 includes a machine base 11, a transport unit 12 that transports a work W, a printing unit 13 that applies ink to the work W and performs printing, and a printing unit 13. A moving unit 14 for moving the ink, a drying unit 16 for drying the ink on the workpiece W, an input operation unit 18 for inputting and setting various conditions during printing, and a control unit for controlling the operation of each unit. 15. In the printing apparatus 1, the control unit 15 is electrically connected to the external power supply source 200.

  In the present embodiment, the direction orthogonal to the conveyance direction for conveying the workpiece W (main scanning direction) is the x direction, the direction parallel to the conveyance direction (sub-scanning direction) is the y direction, and the direction orthogonal to the x direction and the y direction. z-direction.

  The transport unit 12 is disposed on the feeding device 3 that feeds out the long workpiece W wound in a roll shape, the winding device 4 that winds up the printed workpiece W, and the machine base 11. And a support device 5 that supports the workpiece W.

  The feeding device 3 is disposed upstream of the machine base 11 in the feed direction (y-axis direction) of the workpiece W. The feeding device 3 includes a feeding roller (feeding reel) 31 that feeds the workpiece W in a roll shape, and a tensioner 32 that tensions the workpiece W between the feeding roller 31 and the support device 5. And have. The feed roller 31 is connected to a motor (not shown) and can be rotated by the operation of the motor.

  The work W can be made of a thin film having ink absorbability and a thin film having ink non-absorbability. In the case of the former, for example, special paper for inkjet recording such as plain paper, high-quality paper, and glossy paper, and other woven fabrics can be used. In the latter case, for example, a plastic film that is not surface-treated for inkjet printing (that is, an ink absorbing layer is not formed), and a plastic film coated with a plastic on a substrate such as paper or the like Are bonded. The plastic is not particularly limited, and examples thereof include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene.

  The winding device 4 is disposed on the downstream side in the feed direction (y direction) of the workpiece W from the machine base 11 with respect to the feeding device 3. The winding device 4 includes a winding roller (winding reel) 41 that winds the workpiece W in a roll shape, and tensioners 42, 43, and 44 that apply tension to the workpiece W between the winding roller 41 and the support device 5. have. The winding roller 41 is connected to a motor (not shown), and can be rotated by the operation of the motor. The tensioners 42 to 44 are arranged at intervals in this order in the direction away from the winding roller 41.

  The support device 5 is disposed between the feeding device 3 and the winding device 4. The support device 5 includes a main driving roller 51 and a driven roller 52 that are disposed apart from each other in the y direction, an endless belt (belt) 53 that is stretched between the main driving roller 51 and the driven roller 52, and the main driving roller 51 and the driven roller. Tensioners 54 and 55 for applying tension to the workpiece W with the roller 52 are provided.

  The main driving roller 51 is connected to a motor (not shown) and can be rotated by the operation of the motor. Further, the driven roller 52 is transmitted with the rotational force of the main driving roller 51 via the endless belt 53, and can rotate in conjunction with the main driving roller 51.

  The endless belt 53 is a glue belt in which an adhesive layer having adhesiveness is formed on the front surface thereof. A part of the workpiece W is adhesively fixed to the adhesive layer and conveyed in the y direction. During this conveyance, the workpiece W is stably printed. Further, after printing is performed, the workpiece W is peeled from the endless belt 53.

  Similarly to the main driving roller 51 and the driven roller 52, the tensioners 54 and 55 are also arranged apart from each other in the y direction.

  The tensioner 54 can sandwich the workpiece W with the endless belt 53 between the main driving roller 51 and the tensioner 55 can sandwich the workpiece W with the endless belt 53 between the driven roller 52 and the tensioner 54. As a result, the workpiece W tensioned by the tensioners 54 and 55 is fixed to the endless belt 53 and conveyed while the tension is applied. In such a state, the work W is prevented from wrinkling or the like during conveyance, so that when printing is performed, the printing becomes accurate and high quality.

  The printing unit 13 performs drawing (recording) by printing by ejecting ink (ink droplets) onto the workpiece W conveyed by the conveying unit 12. As shown in FIG. 3, the printing unit 13 includes a carriage unit 132 having a plurality of inkjet heads (ink ejection heads) 2.

  The ink contains a dye or pigment as a colorant in water as a solvent, and in this embodiment, four colors of black (K), cyan (C), magenta (M), and yellow (Y) are used. Is used.

  As shown in FIGS. 3 and 4, the inkjet head 2 constitutes a plurality of head rows 135 arranged in the y direction. Further, as shown in FIG. 4, the inkjet head 2 includes a plurality of nozzles 134 arranged in the y direction.

  In the present embodiment, as shown in FIG. 3, the carriage unit 132 includes a head row 135K in which a plurality of inkjet heads 2 that eject black ink Q are arranged in the y direction, and an inkjet head 2 that ejects cyan ink Q. A plurality of head rows 135C arranged in the y direction, a head row 135M in which a plurality of inkjet heads 2 ejecting magenta ink Q are arranged in the y direction, and a plurality of inkjet heads 2 ejecting yellow ink Q are arranged in the y direction. A head row 135Y.

  The carriage unit 132 includes a pair of head rows 135K, a head row 135C, a head row 135M, and a head row 135Y.

  As shown in FIG. 3, the carriage unit 132 is arranged in the order of the head row 135K, the head row 135C, the head row 135M, and the head row 135Y in the left-right direction around the symmetry axis A parallel to the y direction. doing. That is, in the carriage unit 132, the head rows of the respective colors are arranged so as to be symmetric about the symmetry axis A. Note that “left and right” in FIG. 3 indicates “left and right” in the x direction. With such a configuration, it is possible to increase the amount of ink Q ejected in one pass (forward path or return path) of the carriage unit 132 and to improve the printing speed. In addition, a high-quality image can be easily printed.

  As shown in FIGS. 3 and 4, the boundary portion 133 between the inkjet heads 2 constituting the head row is configured so that the head rows of different colors do not overlap in the x direction.

  Specifically, the boundary 133 between the inkjet heads 2 in the head row 135K and the boundary 133 between the inkjet heads 2 in the other color head rows are displaced in the y direction. Further, the boundary portion 133 between the inkjet heads 2 in the head row 135C and the boundary portion 133 between the inkjet heads 2 in the other color head rows are shifted in the y direction. Further, the boundary 133 between the inkjet heads 2 in the head row 135M and the boundary 133 between the inkjet heads 2 in the head rows of other colors are displaced in the y direction. Further, the boundary 133 between the inkjet heads 2 in the head row 135Y and the boundary 133 between the inkjet heads 2 in the head rows of other colors are shifted in the y direction.

  In the present embodiment, the boundary portion 133 between the inkjet heads 2 of the head row of each color is configured to be shifted to the downstream side in the conveyance direction of the workpiece W as the distance from the symmetry axis A increases.

  In the head row of each color, a plurality of inkjet heads 2 are arranged every other direction in the y direction as shown in FIG. 4, and the central axis of the inkjet head 2 in the x direction is the width of the inkjet head 2 in the x direction ( The configuration is shifted by the width in the x direction.

  Further, as shown in FIG. 4, the inkjet heads 2 in each color head row are arranged so as to overlap each other in the y-axis direction. This overlapping portion constitutes the boundary portion 133.

  In the present embodiment, for example, when any one of the head row 135K, the head row 135C, the head row 135M, and the head row 135Y is the first head row, the head is regarded as the first head row. A head row other than the row can be regarded as the second head row.

  In the printing apparatus 1, the workpiece W fed out by the feeding device 3 is intermittently fed (sub-scanned) in the y direction in a fixed state in which the work W is adhesively fixed by the endless belt 53, and the carriage unit 132 is moved relative to the fixed workpiece W. Ink is ejected from the inkjet head 2 while reciprocating (main scanning) in the x direction by 14. This can be performed until printing is completed and an image is formed on the workpiece W. The obtained image may be obtained by multicolor printing (color printing) or may be obtained by single color printing.

  The moving unit 14 supports the printing unit 13 so as to be movable along the X direction during printing. Thereby, the printing unit 13 can reciprocate so as to straddle the work W, and ink can be applied onto the work W during that time. In addition, as a structure of the moving part 14, it is preferable to have a ball screw and a linear guide, for example.

  The drying unit 16 is downstream of the printing unit 13 in the conveyance direction of the workpiece W and is disposed between the support device 5 and the winding roller 41 of the winding device 4. The drying unit 16 has a chamber 161 in which a heater is built. Thereby, when the workpiece | work W passes the inside of the chamber 161, the undried ink on the said workpiece | work W can be dried with the heat of a heater.

  A tensioner 42 and a tensioner 43 are arranged on both sides in the y direction via the drying unit 16. As a result, the workpiece W can pass through the chamber 161 in a tensioned state. In such a state, the workpiece W is prevented from wrinkling, for example, during passage, and thus the ink W can be reliably dried.

  The input operation unit 18 is composed of, for example, a touch panel. An operator who is an operator of the printing apparatus 1 can input various conditions during printing via the input operation unit 18. Various conditions are not particularly limited, and examples thereof include a printing program, a conveyance speed and a thickness of the workpiece W. The input operation unit 18 also serves as a display unit that displays information on the printing apparatus 1.

The control unit 15 is electrically connected to the transport unit 12, the printing unit 13, the moving unit 14, the drying unit 16, and the input operation unit 18, and has a function of controlling these operations. As shown in FIG. 2, the control unit 15 includes a CPU (Central Processing Unit) 151 and a storage unit 152.
The CPU 151 executes programs for various processes such as the print process as described above.

  The storage unit 152 includes, for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory) which is a kind of nonvolatile semiconductor memory, and can store various programs.

  For example, an external power supply source 200 that applies a voltage of 200 V, for example, is electrically connected to the control unit 15. Thereby, power is supplied to each unit of the printing apparatus 1.

  As mentioned above, although the printing apparatus and printing method of this invention were demonstrated about embodiment of illustration, this invention is not limited to this, Each part which comprises a printing apparatus is arbitrary which can exhibit the same function. It can be replaced with that of the configuration. Moreover, arbitrary components may be added.

  In the above-described embodiment, the printing apparatus using four colors of black (K), cyan (C), magenta (M), and yellow (Y) has been described. There may be five colors or more.

  In addition, the printing apparatus and the printing method of the present invention may be a combination of any two or more configurations (features) of the above embodiments.

DESCRIPTION OF SYMBOLS 1 ... Printing device, 2 ... Inkjet head (ink discharge head), 3 ... Feeding device, 31 ... Feeding roller (feeding reel), 32 ... Tensioner, 4 ... Winding device, 41 ... Winding roller (winding reel) , 42 ... tensioner, 43 ... tensioner, 44 ... tensioner, 5 ... support device, 51 ... driven roller, 52 ... driven roller, 53 ... endless belt (belt), 54 ... tensioner, 55 ... tensioner, 11 ... machine base, 12 DESCRIPTION OF REFERENCE SYMBOLS: Conveyance unit, 13 ... Printing unit, 132 ... Carriage unit, 133 ... Border, 134 ... Nozzle, 135 ... Head row, 135K ... Head row, 135C ... Head row, 135M ... Head row, 135Y ... Head row, 14 ... Moving unit, 15 ... control unit, 151 ... CPU, 152 ... storage unit, 16 ... drying unit, 161 ... chamber, 18 ... input operation Department, 200 ... external power supply, A ... symmetry axis, Q ... ink, W ... workpiece

Claims (6)

A transport unit for transporting the recording medium;
A printing unit that performs printing on the recording medium conveyed by the conveyance unit;
A moving unit that moves the printing unit in a direction that intersects the conveyance direction of the recording medium during the printing,
When the moving direction of the printing unit is the x direction and the conveyance direction of the recording medium is the y direction,
The printing unit discharges a first color ink, discharges a first head having a plurality of first nozzles arranged in the y direction, and discharges a second color ink in the y direction. A second head having a plurality of second nozzles disposed,
The first head constitutes a plurality of first head rows arranged in the y direction,
The second head constitutes a plurality of second head rows arranged in the y direction,
The first head row and the second head row are adjacent to each other in the x direction,
At least a pair of the first head rows and at least a pair of the second head rows are arranged symmetrically about the y direction as a symmetry axis,
The printing apparatus, wherein a boundary portion between the first heads and a boundary portion between the second heads are shifted in the y direction on each of the left side and the right side of the symmetry axis. The plurality of first heads of the first head row are alternately arranged in the y direction, and the central axis in the x direction of the first head is shifted by a predetermined distance in the x direction. ,
The plurality of second heads of the second head row are alternately arranged in the y direction, and the center axis in the x direction of the second head is shifted by a predetermined distance in the x direction. The printing apparatus according to claim 1.   3. The boundary portion between the first heads and the boundary portion between the second heads are shifted to the downstream side in the conveyance direction of the recording medium as they are separated from the symmetry axis. Printing device.   The printing apparatus according to claim 1, wherein the transport unit includes a belt having adhesiveness with respect to the recording medium.   The printing apparatus according to claim 1, wherein the moving unit is configured to move the printing unit so that the x direction is orthogonal to the y direction.   6. A printing method comprising printing on a recording medium using the printing apparatus according to claim 1.

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